Best Cheesy Zucchini Gratin Recipe - How to Make Zucchini Gratin

Ingredients

• 2 tbsp. butter (plus more for buttering pan)
• 2 cloves garlic, minced
• 2 tbsp. all-purpose flour
• 1 1/2 c. whole milk
• 2 c. shredded Gruyère, divided
• 1/2 c. freshly grated Parmesan
• Kosher salt
• Freshly ground black pepper
• Pinch nutmeg
• 4 medium zucchini, sliced crosswise into 1/4” coins
• 2 tsp. freshly chopped thyme
• Freshly chopped parsley, for garnish